The RV12 has removable wings and a 20 USG fuel tank which is housed in an aluminium tank that is assembled and sealed by the builder during construction. The fuel tank is fitted behind the pilot and passenger seats in the luggage area in plane speak. The benefit of this arrangement is the simplicity of removing the wings for transport because one does not need to drain or plug off fuel when removing the wings. The downside to this arrangement is the potential for rupturing of the fuel tank, however one could compare all day the merits of fuel in the wings versus in the fuselage. Think back to Christmas day a few years back when the 172 spudded in flat after hitting the power lines with full fuel - it still caught fire and I'm sure there are many other examples out there of the same.
It would be interesting to know how much fuel was carried for the flight. Of the test flying literature I have read prior to undertaking such flights I have been lead to believe that minimum fuel for the flight is always the preference.
Paul G - it's an all metal Vans RV12, the first one to come to grief in Australia as far as I am aware. A very popular kit at the moment with a handful flying and many more under construction.